The present invention is directed to a rolling protective shutter assembly which has a protective shutter, for covering a window or door opening, that may be rolled up into a shutter housing when not in use.
Rolling protective shutters are conventional and are used to provide protection against extreme weather conditions and to deter theft, for example. One such rolling protective shutter is disclosed in U.S. Pat. No. 5,575,322, issued to Miller on Nov. 19, 1996, entitled "Rolling Protective Shutters," which is hereby expressly incorporated by reference herein. As shown in FIGS. 1 and 2 of that patent, the Miller shutter is composed of a plurality of individual slats and a plurality of hinges interconnecting the slats. Each of the slats has a pair of end portions, and the shutter assembly further includes a pair of shutter tracks and means for rolling the shutter from an extended position in which the end portions of the slats are disposed in the shutter tracks to a retracted position in which the shutter is rolled up on a shutter support member.
The shutter assembly of the Miller patent uses a gearbox and hand crank as the means for rolling the shutter between the extended position and the retracted position. In other installations, the gearbox and hand crank are replaced by a pulley and control strap that control the rolling and unrolling of the shutter. In these installations, the pulley is attached to the shutter support member, and the strap is connected between the pulley and a strap recoiler mounted to one of the shutter tracks or to the wall surrounding the opening. The strap recoiler contains a take-up roll upon which the excess strap is stored and a locking mechanism with a brake tab that locks the strap in place when the strap is pulled tight between the pulley and the strap recoiler.
The locking mechanism of the strap recoiler is configured to facilitate retraction and deployment of the strap to roll and unroll the shutter. To roll the shutter to the retracted position, the strap is pulled outwardly away from the shutter track and the opening and downwardly toward the strap recoiler. As the strap is pulled outwardly, the locking mechanism releases the strap and allows the force of a torsion spring within the take-up roll to wind the excess strap onto the take-up roll. At the same time, the control strap is unrolled from the pulley, thereby rolling the shutter onto the shutter support member. When the strap is released, the weight of the shutter rotates the pulley and pulls the strap tight between the pulley and the strap recoiler, thereby locking the locking mechanism.
To unroll the shutter to the deployed position, the strap is pulled outwardly away from the shutter track and the opening and upwardly toward the pulley and shutter housing. As the strap is pulled outwardly, the locking mechanism releases the strap and allows the strap to unwind from the take-up roll. At the same time, the control strap is rolled onto the pulley as the shutter support member rotates due to the weight of the shutter. When the strap is released, the weight of the shutter and the tension in the torsion spring pull the strap tight between the pulley and the strap recoiler, thereby locking the locking mechanism.
In previous strap recoilers, the strap and the brake tab are accessible through an opening in the housing of the strap recoiler. The locking mechanism may be unlocked by depressing the brake tab and releasing the restraining force on the strap. If the shutter is in the retracted position, the weight of the shutter can cause the shutter curtain to unroll and crash down, resulting in damage to the shutter and injury to body parts disposed within the opening. For example, in most pharmacy installations, the strap and recoiler are located on the pharmacy side of the opening for security reasons. A curious customer intrigued by the strap recoiler may reach across the opening and depress the brake tab, thereby causing the shutter to come crashing down on the customer's arm and resulting in injury to the customer and potential liability for the pharmacy. Therefore, a need exists for an improved shutter control strap recoiler that allows deployment of the control strap while preventing inadvertent release of the locking mechanism for the strap.
Previously known strap recoilers do not provide easy access for adjusting the tension in the torsion spring of the take-up roll. The tension in the torsion spring is set during the installation of the shutter assembly. However, after repeated loading and unloading of the spring as the shutter is rolled and unrolled, the metal in the spring may fatigue, resulting in insufficient torque to roll the strap onto the take-up roll. In the presently known strap recoilers, the tension in the torsion spring is adjusted by opening the recoiler housing and/or the shutter housing, and typically necessitates a relatively expensive service call for a simple adjustment. Therefore, a need exists for an improved strap recoiler that facilitates adjustment of the spring tension in the take-up roll without disassembling the recoiler housing and/or the shutter housing.